This Thirst (Tanha) is the craving for life in the widest
sense: the craving for pleasure which propagates life, the craving for
existence in the dying man which brings about another birth, the craving
for wealth, for power, for pre-eminence within the limits of the present
life. What is the nature of this craving and of its action? Before
attempting to answer we must consider what is known as the chain of
causation[442], one of the oldest, most celebrated, and most obscure
formulae of Buddhism. It is stated that the Buddha knew it before
attaining enlightenment[443], but it is second in importance only to the
four truths, and in the opening sections of the Mahavagga, he is
represented as meditating on it under the Bo-tree, both in its positive
and negative form. It runs as follows: "From ignorance come the
sankharas, from the sankharas comes consciousness, from consciousness
come name-and-form, from name-and-form come the six provinces (of the
senses), from the six provinces comes contact, from contact comes
sensation, from sensation comes craving, from craving comes clinging,
from clinging comes existence, from existence comes birth, from birth
come old age and death, pain and lamentation, suffering, sorrow, and
despair. This is the origin of this whole mass of suffering. But by the
destruction of ignorance, effected by the complete absence of lust, the
sankharas are destroyed, by the destruction of the sankharas,
consciousness is destroyed" and so on through the whole chain backwards.

The chain is also known as the twelve Nidanas or causes. It is clearly
in its positive and negative forms an amplification of the second and
third truths respectively, or perhaps they are a luminous compendium of
it.

Besides the full form quoted above there are shorter versions. Sometimes
there are only nine links[444] or there are five links combined in an
endless chain[445]. So we must not attach too much importance to the
number or order of links. The chain is not a genealogy but a statement
respecting the interdependence of certain stages and aspects of human
nature. And though the importance of cause (hetu) is often emphasized,
the causal relation is understood in a wider sense than is usual in our
idiom. If there were no birth, there would be no death, but though birth
and death are interdependent we should hardly say that birth is the
cause of death.

In whatever way we take the Chain of Causation, it seems to bring a
being